Various types of safety devices are provided to prevent an occupant seated in a vehicle or a machine from being catapulted out of the vehicle or the machine due to a collision between vehicles or a collision with other objects.
A seat belt is the representative safety device among the safety devices, and a lower abdomen and a chest of the occupant seated in the vehicle or the machine may be stably secured to the seat by using the seat belt. However, a large amount of load may be applied to the occupant in some instances because collision severity varies based on the types of collisions between the vehicles or with other objects, and safety of the occupant seated in the vehicle or the machine is jeopardized in this case.
Therefore, various technologies are being developed so as to allow the seat belt to exhibit its own function even in a case in which a magnitude of a collision between vehicles or a collision with other objects is large. Among the various technologies, a retractor is in the limelight recently.
The retractor may have a pretensioner which increases a function and an effect of the seat belt by retracting a webbing of the seat belt at the time of a collision between vehicles or a collision with other objects, and an emergency locking retractor (ELR) operating unit which fixes one side of a spool in order to prevent the webbing from being retracted any more after the pretensioner operates.
As illustrated in FIG. 1, a load being applied to a driver's body is continuously increased after a gas generator at a side of the pretensioner operates, and the load is gradually decreased as external force by the gas generator is decreased.
In the case of the retractor in the related art, there occur a locking deep phenomenon in which the applied load is rapidly decreased during the aforementioned process, and an overshoot phenomenon in which the applied load is increased.
Specifically, the locking deep phenomenon refers to a phenomenon in which the applied load is rapidly decreased as a delay occurs during a process in which the ELR operating unit operates after the pretensioner operates, and the overshoot phenomenon refers to a phenomenon in which gas residual pressure of the gas generator hinders the operations of the ELR operating unit and a load limiter, and restricting performance deteriorates due to the phenomena, which causes the driver to be injured in many instances.
Accordingly, there is a need for a method for solving the aforementioned problems.